The present invention is directed generally to the transmission of signals in optical communications systems. More particularly, the invention relates to systems, devices, and methods for privately transmitting information on optical signals.
The development of digital technology provided the ability to store and process vast amounts of information. While this development greatly increased information processing capabilities, it was soon recognized that in order to make effective use of information resources it was necessary to interconnect and allow communication between information resources. Efficient access to information resources requires the continued development of information transmission systems to facilitate the sharing of information between resources. One effort to achieve higher transmission capacities has focused on the development of optical transmission systems. Optical transmission systems can provide high capacity, low cost, low error rate transmission of information over long distances.
The transmission of information over optical systems is typically performed by imparting the information in some manner onto an optical signal. In most optical transmission systems the information is imparted by using an electrical data stream either to directly modulate an optical source or to externally modulate an optical carrier so that the information is carried at the frequency of the optical carrier, or to modulate the information onto one or more subcarriers or sidebands, with the later technique sometimes called sub-carrier modulation (“SCM”).
Initially, modulated optical signals were spatially separated by placing each optical signal on a different fiber to provide space division multiplexing (“SDM”) of the information in optical systems. As the demand for capacity grew, increasing numbers of information data streams were spaced in time, or time division multiplexed (“TDM”), on the single optical signal in the SDM system as a means to better use the available bandwidth. The continued growth in demand has spawned the use of wavelength division multiplexing (“WDM”) to transport multiple optical signals on a single fiber. In WDM systems, further increases in transmission capacity can be achieved not only by increasing the transmission rate of the information on each wavelength, but also by increasing the number of wavelengths, or channels, in the system.
With the increase in data transmission capacities, users, including individuals, businesses, and governments, now utilize applications that require the transmission of private information. Because of the sensitive nature of this information, it is desirable to communicate this private information in a manner to reduce the probability that an eavesdropper will be able to intercept the private information. Also, because optical networks often pass through remote areas, an eavesdropper may gain physical access to an optical fiber or node in the network that allows the eavesdropper to intercept the data carried in the network. For example, amplifier hut sites are typically remote and secluded and are easily penetrated with little risk of discovery. For maintenance and diagnostic purposes, every amplifier has diagnostic optical access ports and connectors that would allow an intruder to extract and/or modify optical signals. Malicious disruption of the traffic is a lower risk since it can be handled by network protection, and would produce serious risk of detection, but eavesdropping and small scale tampering with the data is possible. The private transmission of data may be achieved at various levels, including authentication, data encryption, and transport.
Authentication involves the use of techniques to only allow properly authorized individuals to gain access to and control of a network. This may be done using software and/or by controlling physical access to the network. A software authentication solution may be accessed through a public network and compromised.
Data encryption uses cryptographic encryption techniques that are difficult to decrypt to protect data transmitted in the network. While data encryption is a very powerful at protecting the privacy of information in an optical network, today there are no commercial bulk encrypters/decrypters that are able to encrypt/decrypt data at the high data rates carried on optical networks, e.g., 10 Gb/s or higher.
Transport privacy protection involves preventing an unauthorized eavesdropper from being able to easily collect the data on the network. Transport privacy protection may be used decrease the probability of intercepting the data by an eavesdropper, thereby increasing the privacy of the network. Transport privacy protection may be used alone or with authentication and/or data encryption to increase the privacy of data transmitted in networks. Therefore, there remains a need to provide transport privacy protection to increase the privacy of data transmitted in networks.